Observe, that when God has once given a soul, it abides the same, but the body is taking growth daily. Passing over then the soul as not receiving increase, he makes mention only of the body, giving us to understand that it is not increased by food alone, but by the Divine Providence, from the fact that no one by receiving nourishment can add any thing to his stature. It is therefore concluded, If ye then be not able to do that thing which is least, take no thought for the rest.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. 21. in Matt.